This is a two string alternate picking exercise, similar to the Paul Gilbert alternate picking exercise.
This is the Paul Gilbert pattern. (On the D and G string.)
It’s 9, 10, 12, on D. 9, on G. And 12, 10, 9, On the D again.
This extra version is an alternating, ALTERNATING pattern. So each starting rep actually alternates from an up stroke to a down stroke.
It’s 9, 10, 12, on D. 10, 9, on G. 12, 10, 9, on D.
You can also add the full 3 note per string version that you see in the end of the video.
Hope this helps someone with alternate picking, it’s really helped me.